In current data copying methods and/or systems, for example, a point in time copy of a data storage disk or device in a storage system such as switched virtual circuit (SVC), launch a background process to copy the data from an old disk (source device or disk) to a new disk (target device or disk). While the background process is copying, the method redirects reads of the new disk to the old disk. However if the source disk is space efficient, it will have a potentially large number of unallocated blank regions. If the target disk is fully allocated, these blank regions on the source disk will have to be copied across as zeros to the target disk. This process is disadvantageous when the source disk only has a small amount of real data on it in comparison to the total size of the data storage disk, because the source disk will need to remain part of the copy process while large amounts of zeros (representing blank or empty space on the data storage disk) are being written to the target disk. The source disk is thereby unable to resume normal operations while it is engaged and retained in the copying process, resulting in undesirable data retrieval times for data on the source disk.
Therefore, it would be desirable to provide a method, and system employing the method, for copying data from a source device to a target device without retaining the source device in the copying process while unallocated blank storage regions are copied to the target device.